This invention relates to fuel feeding means for a rotary kiln, and in particular to the re-aiming of a coal burner pipe within the interior of a rotary kiln for controlling flame impingement and for optimizing heat transfer to the material bed and to control clinker ring build-up within the kiln.
From the prior art it is known to feed pulverized coal via a coal burner pipe which is in communication with the interior of a kiln. This knowledge is exemplified by U.S. Pat. Nos. 1,944,452; 1,945,652 and 2,015,866. However, the prior art, as far as it is known, does not concern itself or teach the advantages obtainable with a coal burner pipe that can be re-aimed during operation of the kiln to obtain optimum heat transfer and flame impingement as well as fuel benefits.
In the construction of a plant, positioning of the coal burner pipe prior to the actual operation of the rotary kiln is accomplished by a more-or-less feel for the location for optimum aiming. Since the coal burner pipe is extremely large and heavy and is usually connected to nonyieldable components such as fans and feeders, re-aiming the coal burner pipe is a difficult and time consuming process. It entails shutting down the kiln, dismantling the coal burner pipe and fan and feed equipment; re-aiming the pipe and modifying and reassembling the components, and finally restarting the kiln. It is, of course, appreciated that once proper treatment of the material bed is obtained, the temperature within the kiln is at a very high operating temperature. Thus, to shut the kiln down for the purpose of re-aiming the coal burning pipe is a costly process. For proper heat transfer, the coal burner pipe needs to be aimable after the kiln has gone into operation and judgments can be made for more accurately adjusting the position of the pipe.